Membrane element sealing material holding member and membrane element

Abstract

A membrane element sealing material holding member that even when the dimension of outer diameter of center tube varies, enables holding of the center tube in the center and further enables easy insertion of the center tube; and a membrane element utilizing the same. The membrane element sealing material holding member comprises central opening (19) for insertion of a center tube of spiral membrane element, peripheral orifice (15a) for flowing of a raw liquid into a membrane end portion of membrane element and outer circumferential part (18) for holding of circular sealing material, wherein the central opening (19) has inner circumferential surface (16a) of cylindrical form with a diameter larger than the outer diameter of the inserted center tube, and wherein at three or more positions on the inner circumferential surface (16a), there is provided projection (21) that has sloping face (21a) on its side of center tube (6) insertion and is deformable at the time of insertion of center tube (6) with an outer diameter larger than that of incircle.

Description

TECHNICAL FIELD[0001]The present invention relates to a sealing material holding member that is attached to an end part of a spiral membrane element for holding a sealing material that shuts off the gap between a pressure vessel and the membrane element, as well as to a membrane element using the same.BACKGROUND ART[0002]Conventionally, a spiral separation membrane module is used for a variety of uses such as desalination of brine or sea water, production of ultrapure water, and processing of waste water. As shown in FIG. 7, a spiral separation membrane module has a structure such that a spiral separation membrane element E is housed in a pressure vessel 1, where the gap between the pressure vessel 1 and the element E is shut off with an annular sealing material 4 so as to let the supplied raw liquid 7 flow efficiently into the element E.[0003]The raw liquid that has flown into the element E is subjected to separation with a separation membrane while flowing to the downstream side a...

AI Technical Summary

Benefits of technology

[0010]According to the sealing material holding member of the present invention, a protrusion capable of being deformed at the time of insertion of the center tube having an outer diameter larger than that of the inscribing circle is formed on the inner circumferential surface of the central opening part into which the center tube is inserted. Therefore, even if the outer diameter dimension of the center tube varies, the variation can be coped with by the deformation of the protrusion. At that time, since protrusions are provided at three or more positions on the inner circumferential surface, the center tube can be held at the center of the central opening part. Also, since the protrusion has a tilted surface on the center tube insertion side thereof, the center tube is guided to be inserted by the tilted surface at the time of the insertion, and the protrusion can be smoothly deformed. Also, since the contact area thereof is smaller as compared with the inner circumferential surface even after the deformation of the protrusion, the insertion of the center tube can be carried out easily.

[0011]In the above, a length of the protrusion in an axial direction is preferably below or equal to half the length of the inner circumferential surface in the axial direction. By reducing the length of the protrusion in the axial direction in this manner, the protrusion will be more easily deformed, and also the contact area with the center tube can be reduced, whereby the insertion of the center tube can be carried out more easily. Also, since the length of the protrusion is reduced, the protrusion will be less likely to be observable from the outside after the assemblage, so that the outer appearance is not deteriorated.

[0012]Also, it is preferable that an auxiliary protrusion having a height lower than a height of the protrusion is formed on the inner circumferential surface. By this auxiliary protrusion, even if the amount of deformation of the plurality of protrusions becomes large, the variation of the amount of deformation of individual protrusions can be reduced, whereby the center tube can be held at the center with more certainty.

[0013]Also, it is preferable that the auxiliary protrusion has a tilted surface on its center tube insertion side, and has a bottom surface having a width larger than a width of the protrusion. With this structure, the width of the bottom surface of the auxiliary protrusion is large, thereby providing a structure that is less liable to be deformed. Therefore, even if the amount of deformation of the plurality of protrusions becomes large (even when the outer diameter of the center tube is large), the center tube can be held at the center with more certainty. Nevertheless, the center tube is guided by the tilted surface at the time of insertion, whereby the insertion of the center tube can be carried out easily.

[0014]Meanwhile, the membrane element of the present invention is characterized by including a membrane element sealing material holding member according to any one of the above, a center tube that is inserted in a state in which the protrusion is deformed, and a membrane laminate that is wound in a spiral form around the center tube. According to the membrane element of the present invention, since the sealing material holding member of the present invention is used, the center tube can be held at the center of the sealing material holding member, and moreover the insertion of the center tube can be carried out easily even if there is a variation in the outer diameter dimension of the center tube, as shown by the functions and effects described above. For this reason, the center tube will not be eccentric, and will be a commercial product having a good outer appearance, and a membrane element can be provided by which the operation of attachment to the pressure vessel and the operation of connection of a plurality of membrane elements can be carried out smoothly.

Problems solved by technology

When clearance is increased in consideration of such a variation, the center tube 6 is liable to become eccentric relative to the sealing material holding member 10, thereby aggravating the outer appearance and degrading the commercial quality of the product in some cases.

Also, when the center tube 6 is made eccentric, the operation of attaching the membrane element may become cumbersome depending on the structure of the pressure vessel 1, thereby raising a problem in that the connection operation may become cumbersome in connecting a plurality of membrane elements for use, or the like problem.

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